The present invention relates to devices intended to be actuated by a low energy input, and which output a high energy to the device to be actuated. More particularly, the present invention relates to a booster actuator which uses mechanically stored energy to move an actuator shaft with a force and stroke sufficient to actuate various types of devices.
Those involved in system designs have long required devices which provide a boost or energy level increase to actuate a device. Electric energy input to a solenoid is directly proportional to the output force, which practically limits the use of solenoids in conventional low power electrical systems. A relatively small and inexpensive electrical solenoid may send a signal which will stroke a solenoid plunger, although the force and/or the stroke of the plunger in many cases is insufficient to activate the device intended. Accordingly, boosters have been used between such low energy products, such as solenoids, and a device to be activated to provide the desired energy level to actuate the intended device.
In the fire safety industry, various systems have been devised so that pressurized gas maybe released when a device is manually or automatically actuated. In some applications, a booster or booster actuator may be positioned between a solenoid and a valve, with that valve in turn being actuated to release agents, such as CO2 or a mixture of nitrogen, argon, and carbon dioxide, into the hazard area.
Prior art booster actuators have used magnetized components to hold the actuator in the set or armed position. Many of these actuators require an input force proportional to the desired output force, or require additional electrical circuitry to return the actuator to the set position.
Prior art actuators also include pressurized gas cartridges which are punctured, so that the release of the pressurized gas in response to the puncture may be used to activate a pneumatic device which releases the agent gas to the hazard area. Other types of actuators utilize explosive components to generate the increased energy to activate a valve or otherwise release the agent gas to the hazard area.
Many prior art boost devices have significant disadvantages which have limited their use. Prior art boost devices are relatively complex and/or are not highly reliable, and other devices cannot be easily reset. In still other booster devices, it is difficult to vary the force which activates the boost device and/or to vary the output force from the boost device. The disadvantages of the prior art are overcome by the present invention, and an improved booster actuator is hereinafter disclosed.
In a typical application, the booster actuator of the present invention may be located between a solenoid and a valve. The actuator body houses a cam shaft or force input member which is biased by a coil spring to the initial input position. The body also houses an actuator shaft or force output member which is biased to the activated output position by a plurality of disk springs. A plurality of circumferentially spaced links engage the force input member at one end and the force output member at the other end, and control of the release of the force from the disk springs to the output member in response to movement of the cam shaft. In another embodiment, an electrical coil is provided about the cam shaft, so that a combination solenoid and booster is provided.
It is an object of the present invention to provide a booster apparatus with a force input member and a force output member each movable relative to the actuator body, a biasing member for biasing the force output member to the activated output position and at least one linking member between the force input member and the force output member and pivotably movable with respect to the body from the engaged position to a disengaged position for releasing the force output member to the activated output position in response to the biasing member. The linking member engages both the force input member and force output member, and may cooperate with recesses in the input member and output member for achieving the desired function.
It is another feature of the invention to provide a booster actuator with a force input member, a low force biasing member for exerting a biasing force on the input member, a force output member, another biasing member for exerting a high biasing force on the force output member, and a linking member between the force input member and force output member. Control of the actuator may be reliably obtained by providing two biasing members each of which exert a force independent of the other biasing member on the input member or output member.
It is a feature of the present invention to provide a booster actuator wherein the output force from the actuator may be easily revised without redesigning the remainder of the actuator. Moreover, the change in the output force is independent of the energy required to trigger activation of the booster, and the input energy required to trigger the actuator may be separately selected without regard to the output requirements from the actuator.
It is another feature of the invention that the booster actuator is highly reliable, and may be mechanically reset without the use of electrical devices. The reset may be accomplished quickly and easily, and no replacement of parts is necessary.
It is a further feature of the invention to provide a booster actuator wherein a solenoid coil is provided to control movement of the force input member relative to the actuator body.
It is an advantage of the present invention that the booster apparatus is highly reliable and may be economically manufactured. The booster body preferably seals the internal components from the environment.
These and further objects, features, and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.